The present invention relates to wireless communication mobile terminals and, more particularly, to methods and apparatus that reduce power consumption in a wireless communication mobile terminal.
Extension of battery life continues to be important goal in the design of wireless mobile communication terminals (communication terminals). To reduce the power consumed by a communication terminal when it is not actively carrying out communications with another terminal, the communication terminal can cycle between a sleep mode and an active mode. In the sleep mode, communication circuitry that is used for communication with another terminal via a cellular network is powered off to conserve power. Such communication circuitry can include a high-frequency temperature-compensated crystal oscillator (TCXO), transmitter circuitry, and receiver circuitry.
A mobile network may be configured to page the communication terminal during predefined discrete intervals using a slotted paging channel. For example, in a WCDMA system or a Universal Mobile Telephone System (UMTS), these discrete intervals occur during “paging occasions” when the cellular network transmits a paging indication channel (PICH) that contains 10-millisecond frames, with each frame having 288 bits.
Thus, in order to detect incoming calls, a communication terminal must periodically transition from the sleep mode to an active mode to monitor the paging channel for pages and/or other commands from the cellular network. The communication terminal may also be required to periodically transition from the sleep mode to the active mode to generate and transmit timing alignment updates to the cellular network, to search for adjacent cells for handover decisions, and/or to determine and send geographic location updates to the cellular network.
The duty cycle between the duration of the higher-power active mode relative to the duration of the sleep mode can substantially affect the battery life of the communication terminal.